1. Field of the Invention
The present invention relates to a method of producing a multi-terminal type laminated ceramic electronic component such as a multi-terminal monolithic ceramic capacitor or other suitable device, and in particular, to a method of producing a multi-terminal type laminated ceramic electronic component, the method using an internal electrode pattern in which the shapes of lead-out electrodes which are continuous with an internal electrode are significantly improved.
2. Description of the Related Art
Previously, a variety of multi-terminal type laminated ceramic electronic components have been proposed in which a plurality of internal electrodes connected to plural terminal electrodes are laminated to each other via ceramic layers. For example, in Japanese Unexamined Patent Application Publication No. 2-256216, FIG. 16 schematically shows a multi-terminal type monolithic ceramic capacitor 101. As shown in FIG. 16, a plurality of internal electrodes 103 to 108 are laminated via ceramic layers within a sintered member 102 of the multi-terminal monolithic ceramic capacitor 101. The respective internal electrodes 103 to 108 have lead-out electrodes 103a, 103b to 108a, 108b which are led out to the upper surface of the sintered member 102.
The internal electrodes 103 to 108 are plural lead-out electrodes (not shown) which are led-out to the lower surface of the sintered member 102.
The lead-out electrodes of internal electrodes 103 to 108 adjacent to each other in the lamination direction are alternately shifted from each other. For example, the lead-out electrodes 103a and 103b of the internal electrode 103 are shifted from the lead-out electrodes 104a and 104b of the internal electrode 104. Moreover, the lead-out electrodes 105a and 105b of the internal electrode 105 are positioned so as to overlap the lead-out electrodes 103a and 103b of the internal electrode 103 in the lamination direction.
In the monolithic ceramic capacitor 101, four terminal electrodes are provided on the upper surface of the ceramic sintered member 102. In particular, a first terminal electrode is arranged so as to be electrically connected to the lead-out electrodes 104a, 106a, and 108a of the internal electrodes 104, 106, and 108. On the other hand, a second terminal electrode is arranged so as to be electrically connected to the lead-out electrodes 103a, 105a, and 107a of the internal electrodes 103, 105, and 107. A third terminal electrode is arranged so as to be electrically connected to the lead-out electrodes 104b, 106b, and 108b of the internal electrodes 104, 106, and 108. A fourth terminal electrode is arranged so as to be electrically connected to the lead-out electrode portions 103b, 105b, and 107b of the internal electrodes 103, 105, and 107.
Accordingly, the directions of electric currents flowing in adjacent internal electrodes, e.g., in the internal electrodes 103 and 104, can be set to be opposite to each other by electrical connection of the first and third terminal electrodes to the “hot” side, and also by electrical connection of the second and fourth terminal electrodes to a ground electrode. Therefore, magnetic fluxes generated by the flowing of currents in the adjacent internal electrodes can cancel each other out. Therefore, the equivalent series inductances can be reduced.
Laminated ceramic electronic components such as the monolithic ceramic capacitor 101 are produced by a method in which a plurality of internal electrodes each having plural lead-out electrodes are laminated to each other via laminated ceramic layers, a mother laminate is formed and is cut into laminate chips which are the units of the laminated ceramic electronic component, and then, the laminate chips are fired.
In the formation of the mother laminate, electroconductive paste is screen-printed on a mother ceramic green sheet, so that a mother internal electrode pattern is formed.
FIGS. 17A and 17B are schematic plan views showing mother internal electrode patterns printed on mother ceramic green sheets which are set adjacently to each other in the lamination direction when the above-described type of a laminated ceramic electronic component is produced. In particular, a mother internal electrode pattern 111 shown in FIG. 17A is printed on one of the mother ceramic green sheets. A mother internal electrode pattern 112 shown in FIG. 17B is printed on the second mother ceramic green sheet which is laminated onto the mother ceramic green sheet having the internal electrode pattern 111 printed thereon. A plurality of portions 113 each forming one internal electrode for use in one laminated ceramic electronic component are formed in the mother internal electrode pattern 111. Similarly, a plurality of portions each forming one internal electrode 114 for use in one laminated electronic component are printed on the mother internal electrode pattern 112.
The internal electrodes 113 and 114 are arranged such that when they are laminated to each other, the lead-out electrodes 113a and 113b do not overlap the lead-out electrodes 114a and 114b, and moreover, the lead-out electrodes 113c and 113d do not overlap the lead-out electrodes 114c and 114d, respectively. In the mother internal electrode pattern 111, an internal electrode 113 and the internal electrode 113A adjacent to the internal electrode 113 are formed such that the lead-out electrodes thereof are not continuous with each other. That is, the lead-out electrodes 113c and 113d of the internal electrode 113 are formed so as to be continuous with the lead-out electrodes 113a and 113b of the internal electrode 113A. As described above, the lead-out electrodes of adjacent internal electrodes are formed so as to be continuous with each other. The reason lies in that when a plurality of the mother ceramic green sheets are laminated to each other and cut in the lamination direction, the lead-out electrodes are assuredly exposed to the side surfaces of the laminate chips which are formed by the cutting.
However, the following problem occurs. When the mother internal electrode pattern 111 is printed, e.g., in the direction shown by arrow X in FIG. 18 by screen printing using electroconductive paste, the printed internal electrode pattern spreads as shown by arrow A in FIG. 18, and thus, the shape of the internal electrodes can not be exactly printed. In particular, if the screen-printing is carried out in the direction shown by the arrow X in FIG. 18, window portions C at which the outer peripheral edges are surrounded by the internal electrode pattern are formed, since the lead-out electrodes of, e.g., the internal electrode 113 and the internal electrode 113A are continuous with each other. Thus, in the case in which portions surrounded by the internal electrode pattern and not coated with the internal electrode conductive paste exist, the applied conductive paste can not be further extended, and thus, tends to undesirably spread, as shown by the arrow A.
Thus, it has been difficult to produce a laminated ceramic electronic component having desired internal electrodes printed with high accuracy.